JSFiddle - React, Tailwind, and code Playground

JavaScript

var dataset = {  
"dataset":{  
  "Categories":[  
     {  
        "Desserts":[  
           "Sweets",
           "Ice Creams",
           "Pastry",
           "Moose",
           "Jelly",
           "Donut",
           "Custard",
           "Puddings",
           "Cookies",
           "Pies"
        ]
     },
     {  
        "Juices and Beverages":[  
           "Cold",
           "Hot",
           "Fresh",
           "Mocktail",
           "Sodas"
        ]
     },
     {  
        "Indian Breads":[  
           "Plain",
           "Stuffed"
        ]
     },
     {  
        "Salads":[  
           "Green",
           "Vegetable",
           "Fruit"
        ]
     },
     {  
        "Soups":[  
           "Clear",
           "Thick"
        ]
     }
  ]
  }
};
var cats = dataset.dataset.Categories.map(function (item) {
    return Object.keys(item)[0];
});

console.log(cats);